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Oldest human fossils found

Posted on: Wednesday, 11 June 2003, 06:00 CDT

Scientists have unearthed three 160,000-year-old human skulls in Ethiopia that are the oldest known and best-preserved fossils of modern humans' immediate predecessors.

The nearly complete skulls of an adult male and a child and the partial skull of a second adult appear to represent a crucial stage of human evolution when the facial features of modern humans arose.

Discovered in Ethiopia's fossil-rich Afar region, the skulls have clearly modern features -- a prominent forehead, flattened face and reduced brow -- that contrast with older humans' projecting, heavy-browed skulls.

"They're not quite completely modern, but they're well on their way. They're close enough to call Homo sapiens," said Tim White, a University of California, Berkeley paleontologist who was co-leader of the international team that excavated and analyzed the skulls.

Previously, the earliest fossils of Homo sapiens found in Africa had been dated to about 130,000 to 100,000 years, although they were less complete and sometimes poorly dated, White said.

The new skulls, which were dated at between 160,000 and 154,000 years old, are described in two papers that appear in Thursday's issue of Nature.

White and his colleagues assigned the new creatures to a subspecies of Homo sapiens they named Homo sapiens idaltu -- idaltu meaning "elder" in the Afar language.

Two other scientists not involved with the research said the skulls are an important find that fill a big gap in the African human fossil record, the period between about 100,000 and 300,000 years ago.

They agreed with White that the skulls' age and appearance strongly support genetic evidence that modern humans arose in Africa between 100,000 and 200,000 years ago -- and not at multiple locations in Europe, Africa and Asia as some researchers suggest.

Rick Potts, director of the Human Origins Program at the Smithsonian Institution, said the skulls, while still large and thick-boned, are undeniably modern.

Unlike the heavy brows and projecting facial features of earlier humans, in the news skulls those features have retracted dramatically under the braincase and there is a prominent forehead.

Potts said that while White and his colleagues conclude that the fossil skulls are likely those of ancestral subspecies of Homo sapiens, he believes they represent modern Homo sapiens.

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